Index: firmware/App/Controllers/SubstitutionPump.c
===================================================================
diff -u -r20676421ce71cfc51bddaaa9ba95f9e183967aba -r7f56f07660862bc62524c506699193a7e5f48f96
--- firmware/App/Controllers/SubstitutionPump.c	(.../SubstitutionPump.c)	(revision 20676421ce71cfc51bddaaa9ba95f9e183967aba)
+++ firmware/App/Controllers/SubstitutionPump.c	(.../SubstitutionPump.c)	(revision 7f56f07660862bc62524c506699193a7e5f48f96)
@@ -69,15 +69,8 @@
 #define SUBSTITUTION_PUMP_CONTROL_DRV_ENABLE                 0x00                                               ///< bit 5, Substitution pump control enable pump.
 #define SUBSTITUTION_PUMP_CONTROL_DRV_DISABLE                0x20                                               ///< bit 5, active low, disabled. (DRV8434S)
 
-#define DRV8434S_CTRL1_DEFAULT                               0x00
-#define DRV8434S_CTRL2_DEFAULT                               0x8F
-#define DRV8434S_CTRL4_DEFAULT                               0x30
-#define DRV8434S_CTRL5_DEFAULT                               0x08
-#define DRV8434S_CTRL6_DEFAULT                               0x03
-#define DRV8434S_CTRL7_DEFAULT                               0x20
-
 #define CONCENTRATE_PUMP_CONTROL_DRV_TWOFIXTYSIXTH_STEP      0x0A                                                ///< concentrate pump microstep control 1/256th step.
-#define CONCENTRATE_PUMP_CONTROL_DRV_ONE_TWENTY_EIGHTH_STEP   0x09                                                ///< concentrate pump microstep control 1/128th step.
+#define CONCENTRATE_PUMP_CONTROL_DRV_ONE_TWENTY_EIGHTH_STEP  0x09                                                ///< concentrate pump microstep control 1/128th step.
 #define SUBSTITUTION_PUMP_CONTROL_DRV_SIXTY_FOUR_STEP        0x08                                                ///< concentrate pump microstep control 1/64th step.
 #define CONCENTRATE_PUMP_CONTROL_DRV_THIRTYSECOND_STEP       0x07                                                ///< concentrate pump microstep control 1/32nd step.
 #define CONCENTRATE_PUMP_CONTROL_DRV_SIXTEENTH_STEP          0x06                                                ///< concentrate pump microstep control 1/16th step.
@@ -88,10 +81,14 @@
 #define CONCENTRATE_PUMP_CONTROL_DRV_FULL_STEP_71PCT         0x01                                                ///< Concentrate pump microstep control full step with 71% current.
 #define CONCENTRATE_PUMP_CONTROL_DRV_FULL_STEP_100PCT        0x00                                                ///< Concentrate pump microstep control full step with 100% current.
 
-static U32 SUBSTITUTION_PUMP_CONTROL_FORWARD;
-static U32 SUBSTITUTION_PUMP_CONTROL_STOP;
+#define DRV8434S_CTRL1_DEFAULT                               0x00                                                 ///< Full motor current, normal open-load fault behavior.
+#define DRV8434S_CTRL2_DEFAULT                               0x8F                                                 ///< Motor outputs on, 16us off-time, smart auto-tuning current control (quietest/smoothest mode).
+#define DRV8434S_CTRL4_DEFAULT                               0x30                                                 ///< Registers unlocked/writable, basic over current and over temperature protection settings.
+#define DRV8434S_CTRL5_DEFAULT                               0x08                                                 ///< Stall detection off by default, but if turned on it will show up as a fault
+#define DRV8434S_CTRL6_DEFAULT                               0x03                                                 ///< Stall detection sensitivity threshold (low byte).
+#define DRV8434S_CTRL7_DEFAULT                               0x20                                                 ///< Low current ripple setting, spread-spectrum switching enabled (reduces EMI noise).
+#define DRV8434S_CTRL_DEFAULT                                0x7F                                                 ///< Stop State indicator flag.
 
-
 /// Enumeration of Substitution pump states.
 typedef enum SubstituionPumpState
 {
@@ -128,7 +125,9 @@
 static SUBSTITUTION_PUMP_T substitutionPumps[ NUM_OF_SUB_PUMPS ];                                               ///< Array of Substitution pumps' data structure.
 static OVERRIDE_F32_T pumpTargetRate[ NUM_OF_SUB_PUMPS ];                                                       ///< Target substitution pumps' rate (mL/min).
 static U32 substitutionPumpPublishTimerCounter;                                                                 ///< Substitution pump data publication counter.
-static U08 Enable_DRV8434S_Stepper_Driver;                                                                      ///< Enable New Stepper Driver for Substitution Pump.
+static U08 Enable_DRV8434S_Stepper_Driver;                                                                      ///< Enable new stepper driver for Substitution Pump.
+static U32 SUBSTITUTION_PUMP_CONTROL_FORWARD;                                                                   ///< Substitution Pump forward Control.
+static U32 SUBSTITUTION_PUMP_CONTROL_STOP;                                                                      ///< Substitution pump stop state control.
 
 // ********** private function prototypes **********
 
@@ -549,24 +548,27 @@
  *************************************************************************/
 static void checkSubstitutionPumpControl( void )
 {
-    if ( TRUE == getTestConfigStatus( TEST_CONFIG_DD_ENABLE_DRV8434S_STEPPER_DRIVER ) && (Enable_DRV8434S_Stepper_Driver == FALSE ) )
+    if ( TRUE == getTestConfigStatus( TEST_CONFIG_DD_ENABLE_DRV8434S_STEPPER_DRIVER ) )
     {
-        SUBSTITUTION_PUMP_CONTROL_FORWARD = SUBSTITUTION_PUMP_CONTROL_DRV_ENABLE |
-                                            SUBSTITUTION_PUMP_CONTROL_DRV_REVERSE_DIR |
-                                            SUBSTITUTION_PUMP_CONTROL_DRV_SIXTY_FOUR_STEP;
+        if( Enable_DRV8434S_Stepper_Driver == FALSE )
+        {
+            SUBSTITUTION_PUMP_CONTROL_FORWARD = SUBSTITUTION_PUMP_CONTROL_DRV_ENABLE |
+                                                        SUBSTITUTION_PUMP_CONTROL_DRV_REVERSE_DIR |
+                                                        SUBSTITUTION_PUMP_CONTROL_DRV_SIXTY_FOUR_STEP;
 
-        SUBSTITUTION_PUMP_CONTROL_STOP    = SUBSTITUTION_PUMP_CONTROL_DRV_DISABLE |
-                                            SUBSTITUTION_PUMP_CONTROL_DRV_REVERSE_DIR |
-                                            SUBSTITUTION_PUMP_CONTROL_DRV_SIXTY_FOUR_STEP;
+                    SUBSTITUTION_PUMP_CONTROL_STOP    = SUBSTITUTION_PUMP_CONTROL_DRV_DISABLE |
+                                                        SUBSTITUTION_PUMP_CONTROL_DRV_REVERSE_DIR |
+                                                        SUBSTITUTION_PUMP_CONTROL_DRV_SIXTY_FOUR_STEP;
 
-        setFPGAD92CTRL1Reg( DRV8434S_CTRL1_DEFAULT );
-        setFPGAD92CTRL2Reg( DRV8434S_CTRL2_DEFAULT );
-        setFPGAD92CTRL4Reg( DRV8434S_CTRL4_DEFAULT );
-        setFPGAD92CTRL5Reg( DRV8434S_CTRL5_DEFAULT );
-        setFPGAD92CTRL6Reg( DRV8434S_CTRL6_DEFAULT );
-        setFPGAD92CTRL7Reg( DRV8434S_CTRL7_DEFAULT );
+                    setFPGAD92CTRL1Reg( DRV8434S_CTRL1_DEFAULT );
+                    setFPGAD92CTRL2Reg( DRV8434S_CTRL2_DEFAULT );
+                    setFPGAD92CTRL4Reg( DRV8434S_CTRL4_DEFAULT );
+                    setFPGAD92CTRL5Reg( DRV8434S_CTRL5_DEFAULT );
+                    setFPGAD92CTRL6Reg( DRV8434S_CTRL6_DEFAULT );
+                    setFPGAD92CTRL7Reg( DRV8434S_CTRL7_DEFAULT );
 
-        Enable_DRV8434S_Stepper_Driver= TRUE;
+                    Enable_DRV8434S_Stepper_Driver= TRUE;
+        }
     }
     else
     {